O2micro International Limited

O2 Micro, Incorporated

02 Micro International Limited

Serban-Mihai Popescu

Laszlo Lipcsei

Sorin Hornet

Marius Padure

Bill Densham

James Keim

A power system includes a current regulator coupled to a load and for generating an output current having a substantially constant ripple magnitude, and for adjusting the output current according to a sense signal indicative of the output current. In addition, the power system includes a filter element coupled in parallel with the load and for passing an AC (alternating-current) portion of the output current. Furthermore, the power system includes a current sensor coupled between ground and the parallel-coupled filtering element and load, and for providing the sense signal indicative of the output current.

Power systems with current regulation

A battery pack is disclosed. The battery pack includes a battery cell and a cell monitor. The cell monitor is embedded in the battery cell and is operable for monitoring the battery cell and for generating an alert signal indicative of a predetermined condition of the battery cell.

Battery systems with embedded cell monitors

A DC to DC converter to convert an input voltage to an output voltage. The DC to DC converter may include a pair of switches including a high side switch and a low side switch, an inductor coupled to the pair of switches; and a controller. The controller may be configured to estimate a zero crossing of an inductor current through the inductor without directly measuring said inductor current. An associated method is also provided.

Controller for DC to DC converter

An amplifier that receives an input signal and outputs an amplified output signal includes an integration stage, a comparison stage, and a full bridge circuit. The integration stage is be used for receiving a constant common mode voltage, for receiving a first signal representing the input signal of the amplifier, and for generating a ramp signal. The comparison stage coupled to the integration stage is used for generating a pulse width modulation signal according to the ramp signal and according to a hysteretic signal. The full bridge circuit coupled to the comparison stage is used for receiving a power supply and the pulse width modulation signal, and for generating the output of the amplifier.

Low distortion class-D amplifier

A driver package includes an integrated circuit (IC) comprising pull up circuitry capable of turning ON an associated switch and pull down circuitry capable of turning OFF the associated switch. The pull up circuitry may be coupled to a first bonding pad of the IC, and the pull down circuitry may be coupled to a second bonding pad of the IC. The driver package may further comprise a first conductive path coupled between the first bonding pad and a package pin of the driver package, where the package pin is coupled to the associated switch, and a second conductive path coupled between the second bonding pad and the package pin. The first conductive path may further provide a sensed signal representative of state of the associated switch to break before make control circuitry to assist in minimizing a break before make delay time interval.

Break-before-make sensing for drivers

A method includes starting a time count of a time interval at a start of a state change of a switch of a DC to DC converter; monitoring if the switch is in a skip mode; and disabling the skip mode in response to an expiration of the time interval so that the switch changes states at a frequency rate greater than an audible frequency for humans.

A controller for a DC to DC converter is configured to provide a PWM signal in a first state during a first time interval based on an input voltage less a voltage level representative of an output voltage of the DC to DC converter. The controller may provide the PWM signal in the first state based on the time it takes to charge an energy storage element of the controller to a predetermined level. The controller may also provide an estimator of a zero inductor current level in an associated inductor when the energy storage element is completely discharged. The controller may also be a digital controller that counts time pulses to provide the PWM signal. A DC to DC converter including such a controller and associated methods are also provided.

A battery pack including at least one battery cell; first and second battery selector switches configured to allow selective coupling of the battery cell to a power source or load for charging/discharging the battery cell; and a switch controller. The switch controller closes both of the switches to allow charging/discharging of the battery cell when a minimum charge/discharge current level is reached. A battery charging/discharging circuit including such a battery pack and a method of controlling the charging and discharging a battery cell in a battery pack are also provided.

Battery pack and a battery charging/discharging circuit incorporating the same

A switching circuit includes at least one switch, and a controller configured to provide a periodic control signal. The switch is responsive to the periodic control signal to change states with a start of each period, and a frequency of the periodic control signal has a predetermined minimum frequency level greater than an audible frequency limit for humans. The switching circuit may be used to control a high side switch and a low side switch in a DC to DC converter. A controller having an input voltage sensing circuit to sense an input of a DC to DC converter without using an additional input pin is also provided. Related methods are also provided. A dual phase controller having a phase selection circuit to select between phases is also provided.

A power management circuit for battery systems composed of a switch defining a single charge/discharge path. The switch is selectively controlled using analog signals to couple a battery to a power source for charging, or to couple the battery to an active load. For charging, the switch is controlled by a controller circuit that monitors the battery voltage, the power source and the individual battery cells. The battery is only coupled to the power source if it is determined that the power source is present and that each of the battery cells is capable of receiving a charge. During discharge, the controller monitors the discharge current from the battery and compares this value to a threshold current. If the discharge current falls below the threshold, the switch is controlled to decouple the battery from the load. In this way, an overcharge condition is avoided if, for example, a power source is reapplied to the system. In a multiple battery system (where the battery and battery circuits are connected in parallel to a load and a power source), the use of the threshold current prevents a cross-conduction between batteries.

Power management circuit for battery systems

A balanced battery cell charging circuit is provided. The circuit includes a comparator for comparing the voltage of a battery cell to a predetermined threshold voltage. If the cell voltage exceeds the threshold value, a bleeder current is generated. In one preferred embodiment, the bleeder current is subtracted from the charging current. In another embodiment, the bleeder current is multiplied, and the multiplied bleeder current is subtracted from a total charging current supplied to the cell. To control the charger circuit, current feedback is provided by monitoring the bleeder current generated against a maximum bleeder current, and adjusting the charging current accordingly. The topology of the present invention provides active cell balancing between cells of a battery, and low total power dissipation of the circuit.

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Campbell, CA, United States of America

Serban-Mihai Popescu